Enhanced optical emission from GaN films grown on a silicon substrate

GaN films have been grown on a silicon-(001) substrate with specially designed composite intermediate layers consisting of an ultrathin amorphous silicon layer and a GaN/AlxGa1-xN (x = 0.2) multilayered buffer by metal-organic chemical vapor deposition and characterized by photoluminescence and x-ray diffraction spectroscopy. It was found that the GaN films grown on the composite intermediate layers gave comparable or slightly stronger optical emission than those grown on a sapphire substrate under an identical reactor configuration. Moreover, the full-width at half-maximum for the GaN band-edge-related emission is 40 meV at room temperature. This fact indicates that by using the proposed composite intermediate layers, the crystalline quality of GaN-based nitride grown on a silicon substrate can be significantly improved. (C) 1999 American Institute of Physics. [S0003-6951(99)01814-8].